1. Technical Field
This invention relates generally to surgical devices for spreading bones, for example to spread the femur and tibia of a leg in knee surgery, and more particularly to a surgical device, capable of one-handed use, for spreading bones while measuring a tension of ligaments about the bones.
2. Background Art
When human joints, such as knees and hips, become aged, diseased, or damaged, modern medical technology permits replacement with artificial joints. Such replacement surgery permits people who would be bound to a wheel chair or bed to walk and enjoy a higher quality of life.
When surgeons perform replacement surgery, as well as when they perform restorative surgery not involving a prosthetic replacement, numerous measurements must be made. By way of example, ligaments hold the human knee together, including the medial and lateral collateral ligaments disposed on either side of the knee. During many surgical and diagnostic operations, a surgeon must separate the femur and tibia of the knee with a spreader. This separation sometimes requires incisions in the ligaments of the knee such that the tension applied by the ligaments is reduced to allow sufficient femoral-tibial separation. It is helpful to know how force the ligaments are exerting prior to making the incisions.
Femoral-tibial spreader devices, such as those manufactured by Innomed, Inc., are available to facilitate femoral-tibial separation. These devices generally have bone-engaging plates that are placed between the tibia condyles and the femur condyles. The plates are then separated, thereby separating the femur from the tibia. A limitation of such devices is that they are not capable of measuring any forces applied by the surrounding ligaments.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.